Balanced wire connector

ABSTRACT

A weatherproof protector module for telecommunication circuits has wire insertion points that are arranged in lateral, forward and rearward symmetry about a single stuffer screw. The module contains J-shaped insulation displacement connectors (IDCs) with slits for engaging the wires. The symmetry of the module allows the screw to exert balanced forces in every direction as the wires engage the IDCs. The module also contains an insulative gel that is extruded around the wire contact locations when the wires are engaged. A wiper seal located each wire insertion point and a thixotropic gel prevent the expulsion of the insulative gel from the module after extrusion.

This application is a continuation application of Ser. No. 09/164,783,filing date Oct. 1, 1998 now U.S. Pat. No. 6,025,982.

TECHNICAL FIELD

This invention relates in general to electrical connectors and inparticular to a weatherproof protector module for telecommunicationcircuits.

BACKGROUND ART

There are several prior art weatherproof protector modules that utilizeinsulation displacement connectors (IDC) to interconnect withtelecommunication circuits. An IDC connector has a blade with asharp-edged slit that cuts through the insulation of an inserted wire toestablish electrical continuity between the IDC connector and the wire.The protector module has a grounded protector device that connects atelephone subscriber wire to a telephone company wire. Under normalconditions, the protector device will not conduct electricity. If theprotector device experiences a voltage overload, it will conduct theoverload to ground to prevent the excess voltage from damaging telephoneequipment located inside a user facility. Protector devices are usuallyeither a solid state device employing thyristors or two plates with agap between them and located in a gas-filled chamber.

In general, IDC-type protector modules have increased in size to provideroom for multiple stuffer screws or a keyed stuffer to provide apositive insertion of the wires. One type of prior art module uses twoscrews that protrude into the housing body and take up more space thancan be afforded in a smaller protector. Another type of prior art modulestuffer does not allow for withdrawal of the subscriber wire because itis desirable to not disturb the customer wire contact once it is made.However, if the subscriber wire must be pulled out, insulation on thesubscriber wire, or the subscriber wire itself, may come off and remainin the stuffer.

A third prior art design recognized the need for an IDC in a smallermodule. This design also has two stuffer screws, each of which inserts atip and a ring wire. This configuration allows each screw to stuff oneof the larger telephone company wires and one of the smaller subscriberwires. Unfortunately, these screws are positioned so that they balancethe “stuffing” stresses from side to side but not from front to back.Thus, the load is always unbalanced.

In addition, this type of module only has room for four IDC wirepositions since the two screws take up so much space. Two of the IDCwire positions are for telephone company wires and two are for thesubscriber wires. There are times when the telephone companies want toprovide a jumper wire, but this design does not have enough wiretermination positions to allow it. Moreover, this module also stuffs thewires down into an opaque base that hides the wire connections fromview. An improved weatherproof protector module for telecommunicationcircuits would be desirable.

DISCLOSURE OF THE INVENTION

A weatherproof protector module for telecommunication circuits has wireinsertion points at are arranged in lateral, forward, and rearwardsymmetry about a single stuffer screw. The module preferably containsJ-shaped insulation displacement connectors (IDCs) with slits for gagingthe wires. The symmetry of the module allows the single screw to exertbalanced forces every direction as the wires engage the IDCs. The modulealso contains an insulative gel that is extruded around the wire contactlocations when the wires are engaged. A seal insert located at eachinsertion point and a thixotropic gel prevent the expulsion of theinsulative gel from the module after extrusion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a module constructed in accordance withthe invention, showing a base and a stuffer;

FIG. 2 is a partially exploded perspective view of the module of FIG. 1;

FIG. 3 is a top view of the module of FIG. 1;

FIG. 4 is a sectional end view of the module of FIG. 1 taken along theline 4—4 of FIG. 3;

FIG. 5 is a sectional side view of the module of FIG. 1 taken along theline 5—5 of FIG. 3;

FIG. 6 is a sectional side view of the module of FIG. 1 taken along theline 6—6 of FIG. 3;

FIG. 7 is a sectional side view of the module of FIG. 1 taken along theline 7—7 of FIG. 3;

FIG. 8 is a bottom view of the stuffer of FIG. 1, showing a first gel inplace;

FIG. 9 is a bottom view of the stuffer of FIG. 1, showing a second gelin place;

FIG. 10 is an upper exploded perspective view of the stuffer of FIG. 1along with its internal components;

FIG. 11 is an upper exploded perspective view of the base of FIG. 1along with its internal components;

FIG. 12 is a lower exploded perspective view of the stuffer of FIG. 1;

FIG. 13 is an enlarged partial perspective view of the module of FIG. 1shown in a closed position;

FIG. 14 is an enlarged partial perspective view of the base of FIG. 1;

FIG. 15 is a partial sectional view of the module of FIG. 1, taken alongthe line 15—15 of FIG. 13;

FIG. 16 is a partial sectional view of the module of FIG. 1 taken alongthe line 16—16 of FIG. 13;

FIG. 17 is an enlarged partial perspective view of the module of FIG. 1,shown in an interim open position; and

FIG. 18 is a partial sectional view of the module of FIG. 1, taken alongthe line 18—18 of FIG. 17.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIGS. 1 and 2, module 11 has a base 13 that is generallyrectangular. A stuffer 15 is moveable relative to base 13 between aclosed position shown in FIG. 1, an intermediate open position, and anopen position. Stuffer 15 is secured to base 13 by a screw 17 that islocated on a longitudinal axis 19. Screw 17 extends through hole 21 instuffer 15 and into a threaded hole 23 in a post 25 protruding upwardfrom base 13. A flange 22 (FIG. 6) within hole 21 causes stuffer 15 tomove upward with screw 17 when screw 17 is rotated counterclockwise. Thematerial of stuffer 15 is preferably a plastic that is sufficientlyclear so as to be able to see wires contained therein.

Stuffer 15 has on its front side an offset upper face 26 that is locatedin the same plane as a lower face 28, but offset rearwardly from it.Upper face 26 is located in a plane on axis 19, parallel to andequidistant between a plane of the back of stuffer 15 and a plane oflower face 28. Two circular apertures 27 are formed in upper face 26.Each aperture 27 is sized to received a wire (not shown) that typicallywill connect module 11 to an outside telecommunications network, andthus for convenience herein will be referred to as a telco wire.

There are two pairs of elongated apertures 29 located in lower face 28of stuffer 15. Apertures 29 have a greater axial length than width. Thewidths of apertures 29 are smaller than the diameter of circularapertures 27 for receiving smaller wires than the telco wires. Thesmaller wires typically lead from module 11 to equipment located withina residence or business and will be referred to herein as subscriberwires.

Referring to FIG. 2, the telco and subscriber wires inserted intoapertures 27, 29 on each side of axis 19 are placed in electricalcontinuity with each other through insulation displacement connectors 31(IDC). There are two of the IDCs 31, one located on one lateral side ofaxis 19 and the other located on the other lateral side of andequidistant from axis 19. Each IDC 31 has a rearward blade 33 thatextends upward and registers with one of the circular apertures 27. EachIDC 31 has a forward blade 35 that is located forward of and parallel torearward blade 33 for registering with one of the pairs of elongatedapertures 29. Forward blade 35 is shorter than rearward blade 33 and islocated the same distance forward of axis 19 as rearward blade 33 isrearward of axis 19.

Each blade 33, 35 has at least one slit 37 with a converging entryway 39at its upper edge as shown in FIGS. 5 and 7. Preferably, forward blade35 has two slits 37 for receiving two subscriber wires, if desired. Eachslit 37 allows its respective blade 33, 35 to spread apart as a wire isbeing pushed downward into it. The edges of each slit 37 are sharp forcutting the wire insulation to establish electrical continuity between aparticular wire and the IDC 31. Rearward and forward blades 33, 35 areformed of a single piece of metal, having a flat base 41 (FIG. 11) anddefining a generally a rectangular J-configuration. Each IDC 31electrically connects one of the telco wires to one or two subscriberwires.

Referring still to FIG. 2, each IDC 31 is located within a cavity or gelwell 43. Gel well 43 is a rectangular enclosure that surrounds a portionof each IDC 31 for containing an insulation gel. Gel well 43 has apreferable height or axial dimension that is approximately ¾ the heightof forward blade 35. Referring again to FIG. 11, each IDC 31 is securedwithin one of the gel wells 43 by a rivet 45. Rivet 45 also serves toelectrically connect its IDC 31 to one end of an excess voltageprotector 47. Protector 47 is a commercially available device that willconduct from one end to its other end only when voltage above a certainlevel is encountered. Generally there are two types, one being a gastube type and the other being a solid state type. Each protector 47 hasone end that electrically connects to one of the IDCs 31 by way of rivet45 and another end that electrically connects to a ground circuitthrough a ground contact 49. If a potential difference between groundcontact 49 and an IDC 31 reaches a sufficiently high level, protector 47will conduct or short to ground to prevent harm to subscriber equipment.

A heat shrink wrap 51 encloses protector 47. A number of elements areshown in FIG. 11 for forming an electrical connection between protector47 and ground contact 49. In the embodiment shown, the various elementsinclude a fusible disk 53 sandwiched between the bottom of protector 47and a metal can 55. Initially an open upper end of can 55 will be spaceda short distance from rivet 45. Fusible element 53 is preferably atin-lead and bismuth alloy having a low melting point. Fusible element53 will melt if the current passing through protector 47 is high enoughto cause it to overheat. Once melted, metal can 55 will move toward andtouch rivet 45, permanently shorting can 55 to rivet 45. Can 55 is inelectrical continuity with ground contact 49 via a spring 57, anothercan 59, and a ground plate 61. If excessive current has been applied soas to damage protector 47, the melting of fusible element 53 places itsIDC 31 in permanent contact with ground 49. When tested, the shortinforms the user that module 11 has been damaged due to excessivecurrent and needs to be replaced.

Referring now to FIG. 4, stuffer 15 has an extruder 63 for each of theIDCs 31. Extruder 63 protrudes downward from the top of stuffer 15 andfits in gel well 43 between IDC blades 33, 35 when stuffer 15 is in theclosed position. This forces gel contained in cavity or gel well 43 toflow throughout the spaces surrounding IDC 31 and seal the wires afterinsertion. Extruder 63 has a front side that is closely spaced toforward blade 35. Extruder 63 also has a pair of slots 65 for guidingsubscriber wires into slits 37. As shown in FIG. 7, small triangularprotuberances 66 extend downward from an interior portion of stuffer 15to register with each entryway 39 of each forward blade 35.Protuberances 66 push the subscriber wires downward into slits 37 andretain them in place. Protuberances 66 are located forward of extruder63. Protuberances 67 for pushing the telco wires into slits 37 ofrearward blades 33 are shown in FIG. 5. Each protuberance 67 is locatedwithin stuffer 15 at its top for registering with each slit 37 ofrearward blades 33. Protuberances 67 are also generally triangular inshape but may be any shape as long as it generally corresponds to theconverging entranceway 39.

Module 11 has a test device to enable a technician to test module 11.The testing device includes a test port 73, shown in FIG. 5, for each ofthe IDCs 31. Each test port 73 has a J-shaped test contact 69 extendingfrom an upper end 71 located on the exterior of stuffer 15 at the top toa lower portion that abuts an edge of rearward blades 33. Continuity maybe checked by connecting a continuity tester between test contact 69 andeach of the wires connected to the particular IDC 31. Also, connecting acontinuity tester between ground contact 49 and test contact 69indicates whether can 55 (FIG. 11) has shorted to IDC 31 through rivet45 due to excessive current.

In the preferred embodiment, module 11 is water resistant so as to servein areas where it might be exposed to excessive moisture. To sealagainst leakage, two types of insulation gels are employed. FIG. 8 is abottom view of stuffer 15, with screw 17 (FIG. 1) not shown and testcontacts 69 (FIG. 5) not shown. Test ports 73 are shown filled with athixotropic gel 75, which is an insulative substance with an additive tomake it thixotropic. That is, once disposed in test port 73, it willremain in that position. Gel 75 will not flow as a liquid would intoother areas, rather has a rubbery texture immediately upon application.Thixotropic gels are commercially available and are normally opaque. Thepurpose of thixotropic gel 75 is to form a seal for test ports 73 beforeapplying a primary insulative gel 77. Primary insulative gel 77, whichis schematically shown in FIG. 9, is poured into the interior of stuffer15 while inverted not long after thixotropic gel 75 has been applied.Primary gel 77 is clear and initially has a low viscosity, much lowerthan the viscosity of thixotropic gel 75. Primary gel 77 will run intothe various spaces in the interior portions of stuffer 15 on each sideof a central engagement member or cavity 78. Central cavity 78 is sizedto slide on post 25 (FIG. 2) and has four walls surrounding screw hole21. Primary insulative gel 77 will also be poured into gel wells 43(FIG. 2) during assembly. The amount of primary insulative gel 77dispensed is calculated so that when stuffer 15 is moved to the closedposition, the extruders 63 will cause the primary gel 77 to fully occupythe open spaces surrounding IDCs 31, but will not be in excess of thevolume of the open spaces so as to be extruded out of module 11. Also,after testing at the factory, some primary gel 77 will be placed in thesmall recesses surrounding the upper ends of test ports 73 (FIG. 10) tocover upper ends 71 of test contacts 69. When dispensed into module 11,gels 75, 77 are uncured, but will cure over time, both having a rubberysoft texture after curing.

Referring to FIG. 10, stuffer 15 has devices to prevent gel 77 (FIG. 9)from being extruded or flowing out apertures 27, 29. These devicesinclude a seal or wiper 81 that is located in the interior of stuffer15, blocking each circular aperture 27. Each wiper 81 is a thin sheet ofthermoplastic that is adapted to be pierced by a telco wire duringinstallation. Alternately a small slit or hole may be placed in eachwiper 81 for receiving a telco wire. Wiper 81 is held in position by aretainer 83. Retainer 83 fits against the interior surface of upper face26. Retainer 83 is a solid rigid plastic member with an aperture 85 thatis of the same diameter and registers with one of the apertures 27.

Similarly, a seal or wiper 87 is employed to block each pair ofelongated apertures 29. Wiper 87 is also a thin sheet of thermoplasticand is adapted to be pierced by a subscriber wire. Alternately, a smallslit or hole may be formed in wiper 87 for receiving a subscriber wire.Wiper 87 is located on the interior surface of lower face 28. A retainer89 holds wiper 87 in place. Retainer 89 is a rigid plastic member withtwo elongated apertures 91 that are dimensioned the same as and registerwith apertures 29. Wipers 81, 87 will thus prevent any extrusion ofprimary gel 77 when stuffer 15 is initially moved to its closedposition.

FIGS. 15-17 disclose a device on module that provides an audible signalwhen stuffer 15 reaches certain positions. One position of importance isan interim open position shown in FIG. 17. In the interim open position,screw 17 has been rotated counterclockwise to raise stuffer 15 highenough so that circular apertures 27 no longer register with rearwardblades 33 of IDCs 31 (FIG. 14). When stuffer 15 moves upward relative tobase 11, the telco wires will move upward with stuffer 15 and disengagerearward blades 33. The subscriber wires on the other hand will still bein engagement with forward blades 35 (FIG. 14) in the interim openposition. This is due to the elongated dimension of apertures 29. Thelower edges of apertures 29 will not pull the subscriber wires fromtheir slits 37 until the lower edges of apertures 29 are above theentryways 39 of forward blades 35. This will not occur in the interimopen position, rather the lower portions of apertures 29 will still beregistering with slits 37. Consequently, the subscriber wires willremain connected. This interim open position allows the technician toperform various functions, and it is important that the technician knowwhen the interim position is reached. If he unscrews screw 17 too much,the subscriber wires will also be withdrawn from IDCs 31, which wouldnot be desirable for certain functions, including checking continuity.If the stuffer provides an audible indication at the interim openposition, unscrewing of screw 17 past that position is less likely tooccur. Also, under some circumstances, an audible indication when thestuffer 15 reaches the closed position would be helpful. The audiblesignal device includes a slot 93 formed in a recess 92 on lower face 28of stuffer 15. Slot 93 is centered between lateral edges of stuffer 15and is formed by two thin bands 94, one on each lateral side of slot 93.A snap member 95 is slidably carried in slot 93. Snap 15 member 95 has alug 97, shown in FIG. 15, that protrudes rearward past bands 94. Lug 97has two shoulders 99 that engage the interior sides of bands 94, asshown in FIG. 16. Lug 97 and bands 94 retain snap member 95 on bands 94,but allow it to slide relative to stuffer 15. Shoulders 99 are small indimension, and bands 94 have some flexibility. An assembler can installsnap member 95 by simply pressing it into slot 93 until its shoulders 99snap against the interior sides of bands 94.

Referring again to FIG. 13, snap member 95 has two laterally extendingarms 101. Arms 101 extend laterally outward toward a side edge of recess92. A protuberance 103 is located on each side edge 92. Protuberance 103is a small triangular shaped member that is dimensioned to contact thetip of one of the arms 101. Although both protuberances 103 could beused, in this embodiment, only the left arm 101 is long enough to becontacted by protuberance 103 when stuffer 15 moves upward relative tosnap member 95. After contact, if sufficient force is applied, arm 101flexes and protuberance 103 moves past arm 101, making a significantsnap or clicking noise. FIG. 17 shows arms 101 below protuberances 103,while FIG. 13 shows arms 101 above protuberances 103.

The mechanism to force snap member 95 past protuberance 103 isillustrated in FIGS. 14, 15, and 18. Lug 97 of snap member 95 protrudesrearwardly into a recess 105 formed in post 25 of base 13. Recess 105has a lower shoulder 107 that faces upward and an upper shoulder 109that faces downward. Lower shoulder 107 is located on the upper end of afinger in the embodiment shown. Lug 97 can move only between the upperand lower shoulders 109, 107. When in the position shown in FIG. 13, alower end of lug 97 contacts shoulder 107. When stuffer 15 moves upward,as shown in FIG. 18, snap member 95 will also move upward a shortdistance with stuffer 15 due to friction and also because the left arm101 will be resting on the left protuberance 103. When the upper end oflug 97 contacts upper shoulder 109, snap member 95 can no longer moveupward with stuffer 15. Continued upward movement of stuffer 15 andprotuberance 103 relative to snap member 95 then causes arm 101 to flexand quickly snap past protuberance 103, giving an audible signal. Thissignal occurs at the interim open position shown in FIGS. 17 and 18.

Similarly, when closing stuffer 15, snap member 95 will move downward inunison with stuffer 15 until the lower edge of lug 97 contacts lowershoulder 107. Continued downward movement of stuffer 15 and protuberance103 deflects arm 101 against protuberance 103, causing arm 101 to snappast protuberance 103 to the position shown in FIG. 13. Again, anaudible signal results, indicating the closed position.

In operation, the technician will rotate screw 17 counterclockwise to afully open position. In the fully open position, both apertures 27 and29 will be located above and out of registry with blades 33, 35 of eachIDC 31 (FIG. 2). The user inserts telco wires into circular apertures 27and at least one subscriber wire into at least one of the elongatedapertures 29 on each side of axis 19. During insertion, the wires willpierce wipers 81, 87 (FIG. 10). The user then rotates screw 17clockwise, moving stuffer 15 to the closed position. As it moves to theclosed position, snap member 95 will move from the position shown inFIG. 17, wherein arms 101 are below protuberances 103, to the positionshown in FIG. 13. During this occurrence, an audible signal is providedto the technician indicating that module 11 has been closed. As stuffer15 closes, extruders 63 (FIG. 4) force primary insulative gel 77 (FIG.9) to flow around the wires and into the open spaces surrounding IDCs31. The wires occupy some volume of the interior, displacing some of thegel. The amount of gel in module 11 is selected so that a slightpositive pressure will be applied to the gel after the wires have beeninstalled and module 11 closed. Wipers 81, 87 (FIG. 10) help to reduceexpulsion of gel out apertures 27, 29 and into the cavities as stuffer15 is closed.

Should the technician wish to remove the telco wires, he rotates screw17 counterclockwise until snap member 95 makes an audible click,indicating the interim open position. This audible clicks occurs due toupward movement of stuffer 15 relative to snap member 95, causing one ofthe protuberances 103 to flex and snap past one of the arms 101 (FIG.13). At the interim open position, the telco wires will have moved outof slits 37 of rearward blades 33. This enables the technician to pullthe telco wires from apertures 27. Wipers 81 (FIG. 10) strip gel fromthe telco wires as they are withdrawn to prevent significant loss ofgel. The subscriber wires remain in place due to the elongated shape ofapertures 29. Additionally, as the stuffer 15 is moved upward by thescrew 17, the extruders 63 will cause, through negative pressure, thegel to be pulled upward from the wires and apertures 27. The gel then isless likely to be removed with the wires. When the stuffer 15 is laterscrewed back down, the gel is again extruded into the open spaces andagain provides the small positive pressure on the gel.

The invention has significant advantages. The placement of an IDCequidistant on each side of the axis provide lateral balance and allowsthe use of a single screw for opening and closing the module. Theforward and rearward blades of the IDCs provide forward and rearwardbalance about the screw. The use of a thixotropic gel seals the testports to enable a low viscosity primary gel to be used within thestuffer without leakage into the test ports during assembly. The use ofa low viscosity gel reduces the chance of bubbles and voids that can bedetrimental. The wipers further seal around the wires and preventexpulsion of the gel when the stuffer is first assembled to the base.The snap member provides an audible indication when the stuffer has beenunscrewed to an interim open position, avoiding unnecessary removal ofthe subscriber wires.

While the invention has been shown in only one of its forms, it shouldbe apparent to those skilled in the art that it is not so limited, butis susceptible to various changes without departing from the scope ofinvention.

I claim:
 1. A protector module for telecommunication circuits,comprising: a base having a bottom, a front, and a back; at least oneIDC mounted to the base, the at least one IDC having a blade thatextends generally upward from the base, the blade having a slitextending downward from an upper end; a stuffer mounted to the base formovement between an upper open position and a lower closed position; atleast one aperture in the stuffer for registering with the at least oneblade for insertion of a wire into engagement with the blade; and atleast one protrusion in the stuffer for pressing the wire into the slitwhile moving from the open to the closed position.
 2. The protectormodule of claim 1, wherein the slit at the upper end has an entrywaywith a predetermined configuration and the at least one protrusion has aconfiguration corresponding to the configuration of the entryway to holdthe wire in the slit when the stuffer is in the closed position.
 3. Theprotector module of claim 2, wherein the predetermined configuration isa triangular shape.
 4. The protector module of claim 1, furthercomprising an overvoltage protector mounted in the base adjacent the atleast one IDC.
 5. The protector module of claim 1, wherein the blade isflat.
 6. A protector module for telecommunication circuits, comprising:a base having a bottom, a front, a back, and a longitudinal axis; a pairof IDCs mounted to the base, one on each lateral side of the axis, eachof the IDCs having a blade that extends generally upward from the base,the blades having a slit extending downward from an upper end; a stuffermounted to the base for movement along the longitudinal axis between anupper open position and a lower closed position; a pair of lowerapertures in the stuffer for registering with the blades for insertionof wires into engagement with the blades; and a set of protrusions inthe stuffer for pressing the first and second wires into the slits whilemoving from the open to the closed position.
 7. The protector module ofclaim 6, wherein the slit at the upper end has an entryway with apredetermined configuration and the at least one protrusion has aconfiguration corresponding to the configuration of the entryway to holdthe wire in the slit when the stuffer is in the closed position.
 8. Theprotector module of claim 7, wherein the predetermined configuration isa triangular shape.
 9. The protector module of claim 6, furthercomprising an overvoltage protector mounted in the base adjacent the atleast one IDC.
 10. The protector module of claim 6, wherein the bladesare flat.